Drive bogies ("Black Beetle" from SEM)
Prototype
Operating companies/organisations
Various
Model
Classification
Chassis, bogies and wheels
Manufacturer and supplier
Item details
Powered by Mashima 1220 or 1224 flat can motor. Wheelbases from 25.5mm to 38mm. Wheel sizes from 9.6mm to 12.25mm.
Wheelbases from 25.5mm to 29.5mm use the Mashima 1220 motor. Speed at 12V is approximately 3.3 scale miles per
hour per scale inch of wheel diameter.
Wheelbases from 29.75 to 38mm use the Mashima 1224 motor. Speed at 12V is approximately 2.3 scale miles per hour
per scale inch of wheel diameter.
Height of centre pivot above rail is 12.4mm plus half the wheel diameter, e.g. with 10.5mm wheels the centre pivot
is approximately 17.6mm above the rail level.
All have 25mm pinpoint axles as standard and include a bracket for fixing sideframes to. Note that sideframes are
not included.
|
order code |
description |
|
D1 |
29.75mm (representing 8ft 6in) wheelbase with 12.25mm (representing 3ft 6in) spoked wheels. |
|
D2 |
As D1 but with disc wheels. |
|
D3 |
28.0mm (representing 8ft) wheelbase with 10.5mm (representing 3ft) disc wheels |
|
D4 |
29.75mm wheelbase with 10.5mm disc wheels |
|
D5 |
34.0mm wheelbase with 12mm disc wheels |
|
D6 |
25.5mm (representing 7ft 3in) wheelbase with 10.5mm spoked wheels. |
Price
Price for a standard Black Beetle is Aus$80.00 [DEC02]. Dummy (unpowered) bogies are Aus$20 each [DEC02]. These prices include Australian GST.
Availability
Current (DEC02)
Notes
Black Beetle drive bogie
The Black Beetle will provide quality performance in a small space and can also be offered in a wide range of wheelbases and wheel diameters, both disc and spoked centres, to suit different applications.
To achieve the small size of the Black Beetle the motor, gears and axles are relatively light and may not provide the robustness that some modellers require. The Black Beetle will, however, provide more than adequate power to drive a typical model rail motor hauling one or two trailers, as well as for multiple units and shunting locomotives.
Operation
The Black Beetle is entirely self contained with its own electrical pickups. Try it out on the track. It will run, but intermittent operation may be a problem because of the unit's light weight. Adding the weight of a model will improve the operation. Wherever possible other wheels on the model should be used for electrical pickup as well.
Installation
Fig. 1 gives key dimensions of the Black Beetle. If the floor of the model is at a suitable height, simply drill a 2.1mm or #45 hole for the bogie centre pivot and secure with the nut provided. On thick floors the nut can be turned over to allow the thread to grip.
If the height does not suit it may be necessary to cut an opening in the floor which is then filled with an adapter plate made from 1.5mm or 0.060" polystyrene sheet.
Adding sideframes
The Black Beetle is provided with 25mm long pinpoint axles and moulded acetal bearings. The top cover is moulded in high impact polystyrene and incorporates brackets to which sideframes may be attached.
The simplest method is to drill a hole in the back of each axle box sufficiently large to clear the axle ends, then glue the sideframes to the brackets hanging down from the top cover. Alternatively, to save drilling, the projecting axle ends can be cut off so they do not interfere with the sideframes.
Where the bogie frame features headstocks which are being modelled, the back of each axle box can be drilled to accept a moulded acetal bearing. Fig. 2 provides information regarding the depth of these holes. The bogie sideframes and headstocks can then be assembled as an open frame around the Black Beetle. The sideframes will then be supported on the projecting axle ends, so the brackets hanging down from the top cover can be cut off.
Weight
As stated previously, the Black Beetle is relatively lightly constructed with 2mm diameter axles and should not be overloaded. To avoid premature wear of the bearing surfaces do not exceed a weight of about 100g on top of the centre pivot. This means that with one Black Beetle and the weight of the body equally shared between two bogies, the total weight should not exceed about 250g.
If this weight does not provide sufficient adhesion to haul the desired load, consideration should be given to adding a second Black Beetle. In this case the pickups of the two bogies should be wired together in parallel.
Wiring
The Black Beetle is self-contained and does not require any additional wiring to operate. Nevertheless, to improve operation, it is desirable to provide pickups on any additional wheels on the model. The motor leads emerge from the top cover at one end and are soldered to tags which form part of the pickups. Wires from other pickups can be run to these tags and soldered in place. Be sure to allow sufficient length in the wires so that the bogie can still pivot. When soldering to these tags make sure that the iron is hot enough to melt solder before starting and do not dwell with the iron. The polystyrene of the top cover will melt if exposure to the heat of a soldering iron is prolonged.
Command control/overhead power supply
To operate the Black Beetle on command control the motor leads should be unsoldered from the pickup tabs. Wires can then be run from the pickup tabs to the control 'chip' and then back to the motor, as for any other locomotive.
A motor lead can also be separated from one pickup tab to provide an alternative supply from overhead wiring. If both rails are common, the wheel pickups can be wired together so all four wheels are providing a current path.
Lubrication
As with any mechanical device, correct lubrication will extend the life of your Black Beetle. Use only plastic compatible lubricants such as Labelle #102 and #108 to lubricate the gears and bearings. Gears should be lubricated with grease. Apply a very small amount of oil to each axle where it runs in the gearbox. Use lubricant sparingly as any excess can enter the commutator of the motor and cause faulty operation.